Global child feeding practices remain suboptimal. In this study, we assess the determinants of age-inappropriate breastfeeding, dietary diversity, and consumption of 3+ types of animal source foods (ASFs) using 11,687 observations from combined data from the Indonesian Demographic Health Survey of 2012 and 2017. We used linear and logistic regression after adjusting for the complex sampling design. Child's age and quality of antenatal care (ANC) were associated with all outcomes. Socio-economic status and labour force participation were positively associated with higher dietary diversity score, ASF consumption, and age-inappropriate breastfeeding. More ANC visits and having consultation at ANC were associated with more dietary diversity. Higher women's knowledge level was associated with more dietary diversity and consuming more ASF. Compared with western Indonesia, more children in eastern Indonesia were age-inappropriately breastfed and had lower dietary diversity. The Indonesian government needs to develop programmes to improve child feeding particularly in eastern Indonesia, focusing on improving dietary diversity and ASF consumption in poorer households and on prolonging breastfeeding in richer households. Women's labour force participation should be encouraged, but programmes for working mothers are also needed to support continued breastfeeding and to express breast milk. ANC and postnatal programmes need improved consultation sessions for child feeding.